For workstation no. 6 (before modernization) there occurred large displacement amplitudes for low frequencies (0.5 Hz and 1 Hz) as well as large vibration speed amplitudes, mainly in the range of 5 Hz, related to the rotational speed of the motor compressor. Both displacements and speeds are of strongly non-stationary character.
On the basis of the data presented in tables 2a and 2b, the diagrams of vibration displacements (fig. 3) and speeds (fig. 4) have been made. As it can be seen in figure 3 and inferred from tables 2a and 2b, the vibration displacements in the case of workstation no. 7 (new foundation of the engine) are many times lower compared to motor compressor no. 6. There is no low-frequency, non-stationary vibration of high amplitudes. As shown in figure 4, the speeds of vibration decreased considerably as well. No influence of load alternative (regime) upon the vibration level has been observed, which was the case of motor compressor no.6.
It must be emphasised that in compliance with the ISO standard, there were reported no cases where the speed of vibration would exceed the level described as good.

4.2. Compressor vibration analysis

The measurements of vertical and horizontal vibration of motor compressors were taken at both workstations.

As indicated, the vibration displacements in the case of motor compressor no. 7, are considerably lower than in the case of motor compressor no. 6, whereas the speeds of vibration are comparable.

4.3. Assessment of antifluctuation bottle vibration during pumping

The levels of vibration displacements have been shown in the form of a bar chart in figure 7. It is apparent that for motor compressor no. 7 the levels of displacement are considerably lower than for motor compressor no. 6. In the case of motor compressor no. 6 high displacement amplitudes were recorded at the A4/1 and A4/2 measuring points, regime 1, for the frequency of 0.5 Hz.